332 research outputs found
Surgical treatment for benign biliary strictures
Objectives: In order to describe treatment options for postoperative benign biliary strictures and find a proper approach for treatment, we describe the presentation and management of postoperative biliary stricture in 64 patients.
Methods: Demographical and clinical data from 64 patients undergoing surgical reconstructions by retrospective methods during the past 6 years were analyzed. Clinical features of Grade I and II group versus Grade III and IV group and bile duct plasty versus biliojejunostomy were compared.
Results: Of the 64 patients, 21 received bile duct plasty and the other 43 underwent biliojejunostomy. Patients with bigger bile duct dilatation had better outcomes than those with smaller one, P=0.0372. Hepaticojejunostomy was correlated to better outcomes than other surgical procedures, P=0.0483. Bile duct plasty was related to Bismuth classification Type I, P=0.0001. But biliojejunostomy was related to Bismuth classification Type II, P=0.0001 and
Type III, P=0.0059. Patients with bigger bile duct dilatation had more biliojejunostomy than those with smaller one, P=0.0001.
Conclusion: Both biliojejunostomy and bile duct plasty had good treatment outcomes. Bile
duct plasty should be confined to patients with a degree of bile duct dilatation less than 1.5 cm and Bismuth classification (Type I). The degree of dilatation, hepaticojejunostomy and postoperative
morbidity were factors statistically correlated to long term outcomes
Ursodeoxycholic acid lowers bile lithogenicity by regulating SCP2 expression in rabbit cholesterol gallstone models
Aims: We designed this study to get insight into the disorder of lipid metabolism during cholesterol gallstone formation and evaluate the effect of ursodeoxycholic acid on the improvement of bile lithogenicity and on expression of lipid related genes.
Methods: Rabbit cholesterol gallstone models were induced by high cholesterol diet. Bile,
blood and liver tissues were obtained from rabbits after 0, 1, 2, 3, 4 and 5 weeks. Bile and blood lipids were measured enzymatically. 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR), cytochrome P450, family 7, subfamily A, polypeptide 1 (CYP7A1) and sterol carrier protein 2 (SCP2) mRNA expressions were detected by using quantitative real-time RT-PCR. Cholesterol saturation index (CSI) was calculated by using Carey table to represent the bile lithogenicity.
Results: Rates of gallstone formation of the 4 and 5 week treatment groups were 100 %, but
that of the ursodeoxycholic acid treatment group was only 33.3 %. Expression of HMGCR
and SCP2 mRNA in the 4 week group was upregulated and that of CYP7A1 mRNA decreased
as compared with the 0 week group. Ursodeoxycholic acid could significantly extend nucleation time of bile and lower CSI. Ursodeoxycholic acid could reduce the expression of SCP2, but couldnāt influence expression of HMGCR and CYP7A1.
Conclusions: Abnormal expression of HMGCR, CYP7A1 and SCP2 might lead to high lithogenicity of bile. Ursodeoxycholic acid could improve bile lipids and lower bile lithogenicity, thereby reducing the incidence of gallstones. So it might be a good preventive drug for cholesterol
gallstones
Model and Data Agreement for Learning with Noisy Labels
Learning with noisy labels is a vital topic for practical deep learning as
models should be robust to noisy open-world datasets in the wild. The
state-of-the-art noisy label learning approach JoCoR fails when faced with a
large ratio of noisy labels. Moreover, selecting small-loss samples can also
cause error accumulation as once the noisy samples are mistakenly selected as
small-loss samples, they are more likely to be selected again. In this paper,
we try to deal with error accumulation in noisy label learning from both model
and data perspectives. We introduce mean point ensemble to utilize a more
robust loss function and more information from unselected samples to reduce
error accumulation from the model perspective. Furthermore, as the flip images
have the same semantic meaning as the original images, we select small-loss
samples according to the loss values of flip images instead of the original
ones to reduce error accumulation from the data perspective. Extensive
experiments on CIFAR-10, CIFAR-100, and large-scale Clothing1M show that our
method outperforms state-of-the-art noisy label learning methods with different
levels of label noise. Our method can also be seamlessly combined with other
noisy label learning methods to further improve their performance and
generalize well to other tasks. The code is available in
https://github.com/zyh-uaiaaaa/MDA-noisy-label-learning.Comment: Accepted by AAAI2023 Worksho
Synthesis and Catalytic Performance of Ni/SiO 2
A series of Ni/SiO2 catalysts with different Ni content were prepared by sol-gel method for application in the synthesis of 2-methyltetrahydrofuran (2-MTHF) by hydrogenation of 2-methylfuran (2-MF). The catalyst structure was investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and temperature programmed reduction (TPR). It is found that structures and catalytic performance of the catalysts were highly affected by the Ni content. The catalyst with a 25% Ni content had an appropriate size of the Ni species and larger BET surface area and produced a higher 2-MF conversion with enhanced selectivity in 2-MTHF
Flutter reliability analysis of Xiangshan Harbor Highway Cable-Stayed Bridges in Service
With the development of bridge structures towards being light weight and having a large span , the overall flexibility, and, hence, wind sensitivity, of the bridge increases. Flutter is one of the pivotal factors considered in the design and operation stage for long-span cable-stayed bridges due to its devastating impact, often intrigued by relatively low instability caused by wind speed. This paper presents a reliability theory-based numerical analysis on bridge flutter stability and its influence law of key parameters using a real bridge, the Xiangshan Harbor highway cable-stayed bridge in China. The analysis starts with creating a full scale of finite element model for the bridge in service to calculate the flutter derivative and time-dominated combining rational function in order to obtain the critical-flutter wind speed, and then the aerodynamic self-excited forces on the bridge and flutter time-history response are calculated to identify the flutter critical wind speed. Further, the influence of key parameters for flutter reliability, including the stiffness of the main girder, wire breaking rate, damping ratio and cable breakage location are analyzed comprehensively to achieve the change law of critical flutter wind speed with these parameters. Considering the uncertainty of the actual parameters, these parameters are taken as random variables, and the reliability index and failure probability of bridge flutter are calculated according to their probability distribution and the Latin hypercube sampling method. On this basis, a few suggestions are put forward for flutter risk-control during the service of this cable-stayed bridge, which can further enhance the design theory for long-span flexible bridges
Boosting CO2 electrolysis performance : via calcium-oxide-looping combined with in situ exsolved Ni-Fe nanoparticles in a symmetrical solid oxide electrolysis cell
Financial support from National Key Research & Development Project (2016YFE0126900), National Natural Science Foundation of China (51672095), Hubei Province (2018AAA057) and the EPSRC Capital for Great Technologies Grant EP/L017008/1. We are grateful to the China Scholarship Council for funding (201806160178).The electrocatalysis of CO2 to valuable chemical products is an important strategy to combat global warming. Symmetrical solid oxide electrolysis cells have been extensively recognized for their CO2 electrolysis abilities due to their high efficiency, low cost, and reliability. Here, we produced a novel electrode containing calcium oxide-looping and in situ exsolved NiāFe nanoparticles by performing a one-step reduction of La0.6Ca0.4Fe0.8Ni0.2O3āĪ“ (LCaFN). The CO2 captured by CaO was electrolyzed in situ by the NiāFe nanocatalysts. The cell with this special cathode showed a higher current density (0.632 A cmā2vs. 0.32 A cmā2) and lower polarization resistance (0.399 Ī© cm2vs. 0.662 Ī© cm2) than the unreduced LCaFN cathode at 800 Ā°C with an applied voltage of 1.3 V. Use of the developed novel electrode offers a promising strategy for CO2 electrolysis.PostprintPeer reviewe
Driving forces and impacts of food system nitrogen flows in China, 1990 to 2012
Food nitrogen (N), which includes animal-food (AN) and plant-food N (PN), has been driven by population growth (PG), dietary changes associated with incomegrowth (DC) andrural-urban migration (M) over the past three decades, andthese changes combined with theirNcost, have caused some effect onNuse in China's food system. Although there is an increasing literature on food N and its environmental impacts in China, the relative magnitude of these driving forces are notwell understood. Here we first quantify the differences in per capita AN and PNconsumption in urban and rural areas and their impacts on N input to the food system during 1990ā2012, and then quantify the relative contributions of DC, PG andMin the overall N change during this period. Our results show that a resident registered as living in city required 0.5 kg more AN yrā1 and 0.5 kg less PN yrā1 than one living in a rural area, in 2012. DC, PG and M accounted for 52%, 31% and 17% of the total AN increase, respectively. These three factors caused 46% of the increased N use for food production over the past two decades. Another 54% was mainly caused by the declining in N use efficiencies of the food system. Foodsourced N loss intensity in urban and rural areas were 502 and 162 kg N hmā2 in 2012, a three-fold difference due to the increasing amount and a linear rural-urbanflowofNinput, and inadequateNrecovery via solid waste and wastewater treatment in cities. Our study highlights China is facing higher risks of environmental N pollution with urbanization, because of the high demand for AN and higher food-sourced N loss intensity in urban than in rural areasThis manuscript is based on the several projects, sponsored by the
National Basic Research Program of China (2014CB953801), the Young
Talents Projects of the Institute of Urban Environment, the Chinese
Academy of Sciences (IUEMS201402) and the National Natural Science
Foundation of China (31500391)
Identification of microRNAs Involved in the Host Response to Enterovirus 71 Infection by a Deep Sequencing Approach
Role of microRNA (miRNA) has been highlighted in pathogen-host interactions recently. To identify cellular miRNAs involved in the host response to enterovirus 71 (EV71) infection, we performed a comprehensive miRNA profiling in EV71-infected Hep2 cells through deep sequencing. 64 miRNAs were found whose expression levels changed for more than 2-fold in response to EV71 infection. Gene ontology analysis revealed that many of these mRNAs play roles in neurological process, immune response, and cell death pathways, which are known to be associated with the extreme virulence of EV71. To our knowledge, this is the first study on host miRNAs expression alteration response to EV71 infection. Our findings supported the hypothesis that certain miRNAs might be essential in the host-pathogen interactions
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